I think an application that allows to start a conversation with several contacts, or with a group (already existing) of contacts would be good. Thus, we would send a message to a group, a conversation would be created, and all the responses would come in a single conversation. Because for now, when we send a message (SMS or IM) to several contacts, it opens several conversations, which is not very ergonomic. Then, in that conversation, we should be able to answer a message, by selecting the contact(s) we want to send it to, or by choosing an 'send to all' option. So in this conversation, at the left of the messages, we would see the icon of the sender, and just beside, the icon of the receiver, or an icon that represent the group. What do you think ?